Electrospinning
is an effective method to prepare polyvinylidene
fluoride (PVDF) piezoelectric fibers with a high-percentage β
phase. However, as an energy conversion material for micro- and nanoscale
diameters, PVDF fibers have not been widely used due to their disordered
arrangement prepared by traditional electrospinning. Here, we designed
a near-field electro-spinning (NFES) system driven by a triboelectric
nanogenerator (TENG) to prepare PVDF fibers. The effects of five important
parameters (PVDF concentration, needle inner diameter, TENG pulse
DC voltage (TPD-voltage), flow rate, and drum speed) on the β
phase fraction of PVDF fiber were optimized one by one. The results
showed that the electrospun PVDF fibers had uniform diameter and controllable
parallel arrangement. The β phase content of the optimized PVDF
fiber reached 91.87 ± 0.61%. For the bending test of a single
PVDF fiber piezoelectric device, when the strain is 0.098%, the electric
energy of the single PVDF fiber device of NFES reaches 7.74 pJ and
the energy conversion efficiency reaches 13.5%, which is comparable
to the fibers prepared by the commercial power-driven NFES system.
In 0.5 Hz, the best matching load resistance of a PVDF single fiber
device is 10.6 MΩ, the voltage is 6.1 mV, and the maximum power
is 3.52 pW. Considering that TENG can harvest micromechanical energy
in the low frequency environment, the application scenario of the
NFES system can be extended to the wild or remote mountainous areas
without traditional high-voltage power supply. Therefore, the electrospun
PVDF fibers in this system will have potential applications in high-precision
3D fabrication, self-powered sensors, and flexible wearable electronic
products.